Brodhead Pietenpol Association

Original Posted By: Jeff Boatright
For those of you already flying, how many of you have had to move your wing fore/aft after the first flights? If not, what extra precautions did you take to make sure that you had the strut and roll wire holes in the correct locations? I am making sheet metal, and I am wondering what I can do to make sure that I get the locations correct the first time and not have to remake sheet metal if I have to move the wing.Gene________________________________________________________________________________Date: Sun, 7 Mar 2010 11:55:51 -0500

Original Posted By: Gene Rambo
Good question Gene. I am at the same point and have the same concerns.Rick Schreiber----- Original Message -----

Original Posted By: Tim Willis

Original Posted By: owner-pietenpol-list-server(at)matronics.com
Gene,I moved my wing back a total of 4". I had already planned to move it back2-1/2" but the final weight and balance indicated another 1-1/2" wasnecessary. When I did the sheet metal around the cabanes I left some slopin the holes to allow some movement. It doesn't take much. One inch ofmovement at the top of the cabanes only requires about 1/16" at the bottom.My advice would be to move the cabanes as far aft as you think you wouldneed, then cut the hole about 1/8" bigger than that. You can keep it prettytight to the strut. Cutting it after the fact is not that hard (I had to doa little cutting) but putting the metal back if you cut the hole too big isfarily difficult.One word of caution - Make the holes no bigger than than need to be (withthat 1/8" gap mentioned above). Apart from looking better with the cowlingfitting fairly tightly around the struts, the bigger the hole the more rainwater you will get in. Some water will get in anyway, because the holeshave to be big enough to allow access to the bolts holding the strut to thefuselage.Jack PhillipsNX899JPRaleigh, NC _____

Original Posted By: Tim Willis

Original Posted By: Ben Charvet

Original Posted By: Jack Phillips
I'm sorry guys, but you are not answering the question. Jack, you moved the wing back 4" WHEN? AFTER you flew it? Did you do a final weight and balance before you made your sheet metal? If not, when did you do a weight and balance? several times at different points in construction??I have no idea how far back I "think I need" to move the cabanes, where does that dimension come from? The entire question is directed at not making the holes any bigger than they have to be, and NOT, hopefully, trimming them after first flight, which requires repainting, etc at the least, and remaking the metal at the worst.Please help,Gene ----- Original Message -----

Original Posted By: Ben Charvet
Ben, I did not think of listing the aileron cables because I am running my cables like the original, out the sides and up the struts, not criss-crossing and going inside the wing.Gene ----- Original Message -----

Original Posted By: owner-pietenpol-list-server(at)matronics.com
Gene,I would recommend a quick W&B check before you do the sheet metal around thecockpits. I didn't and ended up moving the wing backwards to get the W&Bcorrect. It left big holes for the aileron control cables and added morescrew holes for the windscreen.CheersPeterWonthaggi Australiahttp://www.cpc-world.com

Original Posted By: owner-pietenpol-list-server(at)matronics.com
Sorry Gene, I misunderstood your question.I did a preliminary weight and balance on an Excel spreadsheet (attached,see "Pietenpol Weight Balance") when I first began assembling the airplane,making my best guesses (which turned out to be not very accurate) of theweight of fabric and paint and any other components not yet installed. As Iadded components I measured the arm and the weight of eac component andadded them to the spreadsheet. This weighing was done with bathroom scales.I used this spreadsheet to estimate how far back my wing needed to be. Thenwhen I moved the ariplane to the airport and assembled it for flight Iweighed it again with certified aircraft scales and found that I needed tomove the wing back another inch to keep the CG forward of 35% of the chordwhen flying solo with a full fuel tank. I have also attached thatspreadsheet ("Pietenpol Actual Weight Balance 2")I went back and reviewed my numbers just now. Initially I had the wing2.68" aft of vertical. After doing the actual weight and balance I moved itback to 3.75" aft of vertical, not 4". However, 4" would probably have beenbetter since the CG is at 35% of the chord as it is. It IS a bit sensitivein pitch but other than that I've seen no problems with the CG that far aft.I have not tried to spin the airplane and don't intend to.As I recall I did have to trim the holes a bit, but just did it with aDremel tool and touched up the edges with paint.Feel free to use the spreadsheets and plug in the numbers for your weightsand moment-arms. I chose to use the firewall as the datum, so anythingforward of the firewall must have a negative value for its arm. Any items Ihave listed that you don't have, such as radios or transponders, just plugin their weight as "0.00".What can be learned from doing such a preliminary weight and balance? Well,I learned that fabric and paint (particularly polyurethane paint) weighs ALOT more than I thought. I'll bet I've got 60 lbs of paint on thatairplane.Good luck,Jack PhillipsNX899JPRaleigh, NC _____

Original Posted By: Ben Charvet

Original Posted By: Dan Yocum

Original Posted By: Jack Phillips
Thanks, Jack, that is exactly the kind of information I was looking for. I have always been particularly critical of weight and balance prior to completion for the exact reason you give, the fabric/paint weighs a LOT more than most people think, but this must be one case where it is called for. I am ready to build sheet metal, but not ready to mount wing, so a W&B right now is not possible. Not sure where to go right now, but desperately trying to finish in time for Brodhead. I'll probably build and slip roll the metal but not cut any strut or cable holes just yet.Gene(making sheet metal, ready to cover fuselage, wing finished but not varnished (winter caught it before I could), no wing struts cut to length yet) ----- Original Message -----

Original Posted By: "Cuy, Michael D. (GRC-RXD0)[ASRC Aerospace Corporation]"
The wing on 41CC is set back 4", that isto say that the cabanes are slanted back4" from vertical. However, it makes abig difference which engine you have...mine is a Continental but there are bothheavier and lighter engines and thatseems to be the biggest factor in theamount of slant needed so don't justcrank in 4" aft slant without doing theW&B calcs. The other big factor is howlight you built the tail ;o) Believeit or not, the type of tailwheel (orskid) could make a considerable differencebecause that weight is about as far aftas anything on the airplane and 1 lb.back there can make a big change.By all means, run several what-ifs forloading in the W&B spreadsheet. What Ifound out from doing mine is that theairplane absolutely must be soloedfrom the back seat unless a very specificset of loading conditions exist. Iplacarded the airplane "Rear Seat SoloOnly". Another thing I found out isthat there is a minimum required pilotweight when soloing (from the rear seat)with full fuel... it's something like90 lbs. and if the pilot is lighter thanthat, the CG falls out of the forwardlimit and the airplane may not haveenough elevator authority to flare itin the landing or pull it off the ground.I haven't experimented in the air withthose loadings; it's all on paper (orin the spreadsheet, that is).Oscar ZunigaAir Camper NX41CCSan Antonio, TXmailto: taildrags(at)hotmail.comwebsite at http://www.flysquirrel.net ________________________________________________________________________________

Original Posted By: "kevinpurtee"
Subject: Pietenpol-List: engine out/ gliding in a PietenpolLoved you post about the brick Jack. Very close to reality.Once in a while I will chop the power abeam the runway threshold numbers to idle and you almost immediatelyhave to start your left turn to base and make it a semi-circle rather than two 90 degree turns.The Pietenpol has the steepest power off glide angle of any airplane I have flown. Much like an ultralight with all ofthose cables, structure, and drag-inducing thangs sticking out.The only thing worse than trying to make a field or highway with an engine out in a Pietenpol is trying to do it with aheadwind !Seriously, if you think you can make a certain field or highway engine-out in a Piet, pick the next field or highwayCLOSER to you to be assured you'll make it.Mike C.________________________________________________________________________________Subject: Pietenpol-List: Re: engine out/ gliding in a Pietenpol

Original Posted By: "kevinpurtee"
In the process of getting my tailwheel endorsement last summer I flew a coupleof hours bootleg in a luscombe and 3 official hours in a cub. After gaining theendorsement I flew 2 hours in a Decathlon for stall/spin awareness and then,strictly for fun, bought an hour in a stearman. The stearman was the best prepfor the piet: pull the power off and down you come.I try to shoot all my landings at idle. My patterns are tight.Respectfully,Kevin PurteeNX899KPRead this topic online here:http://forums.matronics.com/viewtopic.p ... ___Subject: Pietenpol-List: Re: wing placement

Original Posted By: "TOM STINEMETZE"
Gene - My wing is also sloped back 4 inches (corvair). Sounds like that's whata lot of people have. Gives you a place to start. I had to clearance the holes for the wires because I originally fitted everythingwith the cabanes at 90 degrees. When I was done clearancing I covered thelarger holes with neatly cut slotted leather covers. Came out ok.Kevin PurteeNX899KPRead this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Mon, 08 Mar 2010 09:48:40 -0600

Original Posted By: Oscar Zuniga
Wow, Oscar, you are the only person I have ever heard of who had a FORWARD CG problem! LOL, lucky you.Gene ----- Original Message -----